Color Blindness

One of my best friends has a color vision deficiency, or “color blindness,” as it is also known.  Being as that we are best of friends, I have asked him on several occasions to describe what he sees as I compare it to what I see when looking at things like posters, movies, the sky, and other colorful things so I could get a sense of how our vision was different.  He’s also the first to poke fun at himself when he shows up somewhere in purple pants and an orange sweater, or something as equally hilarious as that.  “I had no idea, because, you know, I CAN’T SEE THOSE COLORS!”

The condition my friend has is called Protanopia, or basically a complete lack of red photoreceptors in the retina.  Red hues appear black or dark; it is hereditary, sex-linked, and present in 1% of all males, according to Wikipedia’s article on color blindness.  Protanopia is a form of Dichromatism – this is what occurs when one of the cone pigments of the retina, and color vision is reduced to two dimensions.

I’ve often asked him if it’s weird not being able to see a certain spectrum of colors, to which he often responds with “I have no idea, I’ve never been able to see that color, so how would I know?”  I always feel pretty ridiculous after I ask him that.

One of the most important aspects to know about color blindness is that people with color vision impairment don’t “confuse” colors or swap them in their mind – like “red is green,” “blue is yellow,” etc.  Most people exhibiting color vision impairment learn to tell colors apart by their placement or location (like a traffic lights) or textures (like camouflage).

Look at the differences in colors as seen by people with differing forms of color vision impairment:

As seen by a person with normal color vision:

The same flag, as seen by someone with Protanopia (no red receptors):

Same flag again, but this time seen by someone with Deuteranopia (no green receptors):

Same flag once more, this time as seen by someone with Tritanopia (no blue receptors).  Tritanopiais very rare:

The website Vischeck ( can simulate color deficiencies on images that you upload- it’s an interesting foray into color vision deficiency.  Check it out.

3 replies
  1. On Stage Lighting
    On Stage Lighting says:

    Hi Jim

    Here’s my experience. I have a degree of colour vision deficiency – I know this because the medical guys tell me. All my male cousins have the same “colour blindness”, as you point out it is hereditary.

    I am also a lighting designer and one of quite a few LD’s I know that are technically “colour blind”. A persons eyes are their only reference of colour in the world, and so as a comparison tool it doesn’t really matter. We all see colours how we see them and can tell if one blue is more red than another with more green in it.

    Of course if the receptor impairment was more serious, then that would be a different story. I just love to throw my “colour blindeness” into a conversation alonside all those sound engineers who are deaf ( let’s face it, pretty much all of them).

    Best wishes,


  2. Jim
    Jim says:

    Nice comment, thanks Rob!

    Do you find that any of your color deficiency issues interrupt your intensity perception?

  3. On Stage Lighting
    On Stage Lighting says:

    Not sure how I would know if mild colour deficiency has an effect on intensity. It’s all about contrast and a relative scale. There can’t be much wrong with my deficient receptors – at least not enough to actually skew the intensities.

    On an unrelated note, not wearing my glasses when plotting intensity definitely does. If your eyesight means that you struggle to focus on the subject, your instinct makes you throw more light at the stage to make your iris smaller ( this usually helps with DOF and poor focus caused by astigmatism).

    Putting on my glasses, I find that things are much “hotter” than they need to be.

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